This invention relates generally to digital data transmission systems. Specifically, this invention relates to systems which extract time division multiplexed (TDM) data frames from a data stream. More specifically, the present invention relates to systems which rely on a synchronizer circuit to identify the correct timing associated with particular frames.
Synchronizing circuits typically monitor an incoming data stream for the occurrence of a predetermined synchronization pattern. It is desirable to identify the synchronization pattern quickly. After noting instances in time when synchronization patterns occur, the synchronizer possesses the information needed to de-multiplex the data stream.
Typically, synchronizers represent relatively complicated circuits because they modify local timing of the synchronizer to match the timing presented with the incoming data stream. Some synchronizers attempt to identify synchronization patterns more quickly than necessary for many applications and increase circuit complexity as a result. Other synchronizers utilize programmable microcomputers which identify synchronization patterns slowly and require relatively complicated circuits for their implementation. This excess complication causes undesirably expensive and unreliable synchronizers.